A farce requires five basics:

• Lots of slamming doors.

• Energetic actors willing to make fools of themselves and take off their clothes.

• A steady flow of adolescent sex talk and situations.

• Sight gags galore.

• An easy and obvious target to lampoon.

"What the Butler Saw," the latest offering of the Pittsburgh Irish & Classical Theatre, follows the check list faithfully. There's an added dimension -- it's British, not French -- so it clings to a kind of traditional prudishness, like an old tea cozy too dear to part with.

First, though, is PICT's spirited production of this 1969 play by Joe Orton. A mix of stage veterans and younger players, the cast blazes through the frantic paces with brio and the timing that's essential to farce.

It might help that it's directed by a Brit, Simon Bradbury, an actor and playwright as well, who understands the aesthetics of farce and the typically English brand of humor in this one.

The vets are Helena Ruoti, Douglas Rees, Jeffrey Carpenter and Martin Giles. The youngsters are Amanda Jane Cooper and Sam Trussell.

Giles will lose many pounds during the show's run. Sweating more profusely than a Penguins die-hard in the third period, he carries the physical load as Dr. Rance, the crazy bureaucrat supervising mental health facilities such as the one run by Dr. Prentice. That's Rees, who's interrupted in the seduction of a kewpie-doll job applicant (Cooper) when his wife, played by Ruoti, shows up. She's fresh from a romp with a hotel porter (Trussell) who then arrives with a blackmail threat.

Finally, Carpenter, as the typically dense cop, drops in to the clinic determined to arrest somebody, anybody, everybody.

You now see why multiple doors are a necessity.

Clothes soon come off, dresses end up on men, trousers on a woman and, as it usually does in most farces, a butt is bared. Thank goodness for the spray-on tan.

"What the Butler Saw" is a crowd-pleaser, cleverly staged to roll out the laughs with those sight gags, including the sturdy manhood of a destroyed statue. The performances are sturdy as well, with Giles leading the way as the chief buffoon and the game Ruoti, usually playing more noble roles, not far behind as the proper nymphomaniac. (She's British, you see.)

Orton, a wunderkind of the '60s London theater world, was influenced by the absurdist comedy of "The Goon Show" radio broadcast that produced Peter Sellers, and the much smarter and more satiric "Beyond the Fringe."

That kind of "too clever by half" wordplay keeps "What the Butler Saw" from sinking into garden-variety slapstick, although its climax (sorry, Joe) deteriorates into a too-obvious cliche.

Lunatics are running the asylum, yet despite Orton's reputation as sexual provocateur, "What the Butler Saw" never quite lets go and fully accepts its raunchiness.